The invention relates to a filter arrangement of a heating or air-conditioning system in a motor vehicle consisting of at least two filters which can be flowed through one after the other.
A filter arrangement of this type, which consists of three filters disposes one behind the other and is combined to form a construction unit, is known from German Patent Document DE 3,802,356 A1. If, in this case, the capacity of one of the filters has been reached, the entire construction unit has to be exchanged. This system incurs high costs, in particular in the case of highly effective pollutant filters, such as chemical absorption filters and activated carbon filters, which, by experience, have a longer service life than an upstream paper dust filter.
An object of the invention is to provide a filter arrangement which allows a specific exchange of individual filters to be carried out, for example in accordance with a servicing schedule, in conjunction with a non-confusable assembly possibility which guarantees a high degree of functional reliability even in the case of difficult installation conditions which cannot be viewed directly by servicing personnel.
This object is achieved according to preferred embodiments by providing a filter arrangement of a heating or air-conditioning system in a motor vehicle consisting of at least two filters which can be flowed through one after the other, the filters having different external dimensions and their reception locations having reception sizes assigned to the external dimensions so that each reception location is only able to receive a predetermined filter, wherein external dimensions of the filters decrease in the throughflow direction, wherein a first of the filters, which has the shortest service life, has the largest external dimensions and is located nearest to a filter exchange access, and wherein further of the filters, which have respective smaller external dimensions, are exchangeable respectively after removal of an upstream one of the filters with the next larger external dimensions.
A filter arrangement according to the invention which takes practical conditions into consideration is distinguished by the fact that the external dimensions of the filters decrease in the throughflow direction and that the filter with the shortest service life has the largest external dimensions and is located nearest to an access.
In an exemplary preferred embodiment of the invention, the filter with the smaller external dimensions is exchangeable after removal of the upstream filter with the next larger external dimensions so that the installation and removal of the filter can take place from a central position.
Leakage flows which can lead to annoying dust and odor pollution are prevented if the filters are pressed against assigned filter frames with interposition of seals and with mutual support when the filter provided with the largest external dimensions is secured.
In another exemplary embodiment of the invention, each filter is received by a reception pocket and can be removed and inserted separately in each case.
In a further design of the invention, the filter with the largest external dimensions is a dust filter which, by experience, is spent more quickly than downstream pollutant filters.
The service life of filters arranged downstream of a first filter is increased if the filter with the largest external dimensions can be pivoted away from the following filter and the edge side of this filter located opposite the pivot axis exposes a bypass opening in the pivoted-away state with continued filter throughflow.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.